1. Field of the Invention
The present invention relates to agglomerated particles of water-swellable addition polymers, the agglomerated particles having an average particle diameter of from 20 to 5000 .mu.m and consisting of primary particles having an average particle diameter of from 0.1 to 15 .mu.m, being preparable by polymerization of water-soluble monomers in the presence of regulators and of crosslinking agents in the manner of a water-in-oil polymerization and subsequent azeotropic removal of water from the water-in-oil polymer emulsions, containing the primary particles, in the presence of agglomerating polyalkylene glycols which
(a) are obtainable by an addition reaction of C.sub.2 -C.sub.4 -alkylene oxides with alcohols, phenols, amines or carboxylic acids, and PA1 (b) contain at least 2 polymerized alkylene oxide units, PA1 (a) are obtainable by an addition reaction of C.sub.2 -C.sub.4 -alkylene oxides with alcohols, phenols, amines or carboxylic acids, and PA1 (b) contain at least 2 polymerized alkylene oxide units, PA1 (a) are obtainable by an addition reaction of C.sub.2 -C.sub.4 -alkylene oxides with alcohols, phenols, amines or carboxylic acids, and PA1 (b) contain at least 2 polymerized alkylene oxide units, PA1 where X.sup.- is a halide ion, such as chloride, fluoride, bromide or iodide, or a hydroxide, nitrate, methosulfate, hydrogensulfate or dihydrogenphosphate ion, n and m are each integers from 1 to 2, preferably n=m=2, PA1 Y is ##STR2## PA1 preferably an oxygen atom or a ##STR3## PA1 group, and PA1 R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each a hydrogen atom or an alkyl radical having from 1 to 6 carbon atoms and R.sup.5 and R.sup.6 are each H or an alkyl radical, which can be straight-chain or branched, having from 1 to 18 carbon atoms, preferably from 1 to 6 carbon atoms, or an aryl and/or benzyl radical. PA1 where R.sup.1, R.sup.2 and R.sup.3 may each be H or CH.sub.3 and R.sup.1 may also be C.sub.2 H.sub.5, C.sub.3 H.sub.7 or C.sub.4 H.sub.9, R.sup.4 may be H, C.sub.1 -C.sub.6 -alkyl, benzyl or ##STR5## PA1 and X.sup.- may be an anion, such as Cl.sup.-, Br.sup.-, I.sup.-, methosulfate, ethosulfate, acetate, sulfate, hydrogensulfate or dihydrogenphosphate. Of this class of compounds, the unsubstituted N-vinylimidazole in salt form is preferred. Further suitable water-soluble monomers include N-vinylimidazolines which can be characterized for example with the aid of the following general formula: ##STR6## PA1 where PA1 R.sup.1 =H, C.sub.1 -C.sub.18 -alkyl, ##STR7## PA1 R.sup.5, R.sup.6 =H, C.sub.1 -C.sub.4 -alkyl, Cl, PA1 R.sup.2 =H, C.sub.1 -C.sub.18 -alkyl, ##STR8## PA1 R.sup.3, R.sup.4 =H, C.sub.1 -C.sub.4 -alkyl, and PA1 X.sup.- is an acid radical. PA1 where PA1 R.sup.1 is H, CH.sub.3, C.sub.2 H.sub.5, n- and i--C.sub.3 H.sub.7, C.sub.6 H.sub.5, and PA1 X.sup.- is an acid radical. X.sup.- is preferably Cl.sup.-, Br.sup.-, SO.sub.4.sup.2-, HSO.sub.4.crclbar., H.sub.2 PO.sub.4.crclbar., CH.sub.3 O--SO.sub.3.sup.-, C.sub.2 H.sub.5 --O--SO.sub.3.sup.-, R.sup.1 --COO.sup.- and R.sup.2 =H, C.sub.1 -C.sub.4 -alkyl or aryl. PA1 A) C.sub.10 -C.sub.22 -fatty alcohols with epichlorohydrin in a molar ratio of from 1:0.5 to 1:1.5 to give glycidyl ethers, PA1 B) reacting the glycidyl ethers with (1) saturated C.sub.2 -C.sub.6 -alcohols containing from 2 to 6 OH groups or (2) monoethers thereof with C.sub.10 -C.sub.22 -fatty alcohols, in a molar ratio of glycidyl ether to (1) or (2) of from 1:0.5 to 1:6 in the presence of acids or bases, and PA1 C) alkoxylating the reaction products according to (B) with at least one C.sub.2 -C.sub.4 -alkylene oxide in a molar ratio of from 1:1 to 1:6. PA1 A is a hydrophobic polymer block selected from the group consisting of polystyrene, poly(hydroxycarboxylic acids), polydimethylsiloxanes and polyisobutylenes, and PA1 B is a hydrophilic polymer block from the group of the C.sub.2 -C.sub.4 -polyalkylene glycols.
and disintegrating into the primary particles on introduction into an aqueous medium, to processes for preparing the agglomerated polymer particles, and to their use as thickeners for increasing the viscosity of aqueous systems.
2. Description of the Background
DE-C-36 41 700 discloses a process for preparing water-in-oil emulsions of crosslinked, water-swellable addition polymers by polymerizing water-soluble monomers and crosslinkers in the form of a water-in-oil emulsion using water-soluble azo initiators in the presence of emulsifiers having an HLB value of at least 10. The polymers are not isolated, but are used directly in the form of the water-in-oil polymer emulsions as thickeners, for example for preparing textile print pastes.
EP-A-0 343 840 discloses finely divided crosslinked addition polymers having a particle size of &lt;20 .mu.m. They are prepared by polymerizing water-soluble monomers together with crosslinkers in the manner of a water-in-oil polymerization in the presence of free-radical polymerization initiators. The polymers are again not isolated; instead, the water is merely substantially distilled out of the emulsions and the emulsions are subsequently admixed with an oil-in-water emulsifier to facilitate dispersion of the mixture in water. The polymers are used as thickeners in pigment print pastes. In pigment printing, the thickener remains on the printed textile material together with the binder of the pigment print paste. However, the above-described thickeners are not suitable for textile printing with print pastes which contain soluble dyes, such as reactive dyes or disperse dyes, since such textile prints are subsequently washed and the thickener is not completely removable. The known thickeners remain on the textile material and give it a harsh hand. The known thickeners are also electrolyte-sensitive, so that they are not sufficiently effective on printing with reactive dyes, where the print pastes contain relatively large amounts of salts as well as the ionic dye.
WO-A-92/13912 discloses the agglomerated polymer particles described at the beginning. The agglomerated polymer particles are present in the form of a powder. The crosslinked, water-swellable polymer powders are used as thickeners for aqueous systems, in particular as thickeners for textile print pastes. However, these polymers have the disadvantage that they cannot be washed off and so impart too harsh a hand to the printed material.